Boeing 737 MAX incidents spark safety approval questions

The recent Ethiopian Airlines crash led to the grounding of Boeing’s 737 MAX planes across much of the globe. But as new details emerge about the cause of the model’s second crash within five months, questions are being raised about how the plane's safety was approved in the first place. John Yang talks to Jeff Wise, a pilot and author of a book about MH370, the flight that vanished in 2014.